Torque measuring device for determining the safety of ski foot fastenings



y 6, 1955 J. o. OUTWATER 3,192,767

TORQUE MEASURING DEVICE FOR DETERMINING" THE SAFETY OF SKI FOOTFASTENINGS' Filed April 30. 1963 INVENT OR. JOHN O. OUTWATER FIG.3

United States Patent O 3,192,767 T GRQUE WEASURKNG DEVICE FOR DETERMIN-ENG THE SAFETY OF SKI FOOT FASTENINGS John 0. ()utwater, 62 OverlakePark, Burlington, Vt. Filed Apr. 30, 1963, Ser. No. 276,822 1 Claim.(Cl. 73-439) This invention relates to a force measuring device for skiboot bindings and, more particularly, to a device for measuring thetorque required to cause a boot binding to release.

In attaching a skiers boot onto a ski, it is common practice to utilizea so-called safety binding which releases the toe of the boot from theski when suflicient force, such as the force caused by accidentalturning of a ski, is exerted upon the binding. Safety bindings areusually adjustable so that they may be caused to release uponapplication of a predetermined amount of force. It is desirable thatthey be set so that they will not release under the strains encounteredduring normal skiing, but so that they will release under abnormallyhigh strains so as to avoid snapping of the skiers leg in case of anaccident.

Analysis of the large number of legs broken annually during skiingreveals that most of them result from excessive torsional or twistingforces when the bindings failed to release before the legs snapped.However, some accidents are caused by a binding adjusted so that it willrelease too easily, thereby releasing a ski under non-dangerous strainof normal usage. The skier is thus caught between the Scylla andCharybdis, so to speak, of a binding that may be set to release with theapplication of either too much or too little force. Up until now, therehas been no way, other than by guess, for determining whether thebinding has been set so that, on the one hand, it will break his legbefore it releases or, on the other hand, a ski will come off during theotherwise perfect execution of a slalom. The object of this invention isto provide a device for testing and indicating the torque required torelease a ski boot binding so that the binding may be set to hold a skiboot within known safe limits of tenacity.

These and other objects will be apparent from the followingspecification and drawings, in which:

FIG. 1 is a perspective view showing the invention in typical positionof use;

FIG. 2 is a plan view of the device; and

FIG. 3 is a side elevation of the device.

Referring now to the drawing, in which like reference numerals denotesimilar elements, there is shown a typical ski 2 on which a ski boot 4is held at the rear by a heel plate 6 and, at the toe 8, by a binding10. The details of binding 10 form no part on this invention, and it maybe any one of various safety types, the essential characteristics beingthat the binding will release the toe of the boot if suflicient torqueis applied between the boot and the ski. In most such bindings, thetenacity is adjustable.

The torque measuring device 12 with which the invention is concernedoperates upon the general principles of torque wrenches, of which thoseshown in U.S. Patents 1,775,076; 2,256,478; and 2,803,133 are exemplary,this invention consisting in the recognition of the problem and the newcombination of structural elements to solve it. Device 12 consists of anarm, hereinafter called a dummy last 14 which engages within a ski boot;a post 16 rigidly affixed to the dummy last; and a torque bar 183,192,767 Patented July-6, 1965 aflixed at or near its middle to the topof the post so as to provide two oppositely extending arms 20 and 22; apointer 24 having one end attached to the torque bar at 26, preferablyat or adjacent the middle of the bar; and a scale 28 afixed on one ofthe arms beneath the free end 30 of the pointer.

Dummy last 14 and post 16 are preferably made of metal, of suificientstrength and rigidity to resist bending or substantial deformation underthe forces required for testing the holding strength of the bootbinding. Dummy last 14 need not be of any particular configuration solong as it fits freely into ski boots of various size, and is ofsufficient length so that its front end will engage against one innerside of the boot near the toe of the boot, and its rear end will engageagainst the opposite inner side of the boot near the heel. Post 16should be long enough so that torque bar 18 will be disposed freelyabove the top of the boot. Torque bar 18, also preferably of metal, is asquare bar, and may be provided with hand grips 30 at its ends. Thenecessary deflection characteristics of torque bars of this type arewell known in the torque wrench art, it being apparent that when dummylast 14 is inserted into an anchored boot 4 and the free ends of bararms 20 and 22 are twisted clockwise or counterclockwise, bar arms 20and 22 will deflect equally and oppositely. If pointer 24 be anchored,as at 26, at or adjacent the middle of bar 18, scale 28 will be shiftedlaterally with the deflection of bar arm 22 to which it is attached sothat the free end 30 of the pointer will overlie a scale reading awayfrom the center of the scale. Scale 28 may be calibrated in terms offoot pounds, or in terms of lashing secure, danger for girls, danger formen, etc. While, obviously, the

torque required to break human legs will vary in accord-.

ance with the size and bone characteristics of individuals, reliablestatistics developed by testing on fresh specimens can be used toestablish safe averages for various categories of skiers. Whatever bethe calibration of the scale, the binding should test so that it willnot free the toe of the boot by applying less torque to bar 20 than thatencountered during normal skiing, and yet so that it will release theboot Well below the torque required to snap a leg bone. In accordancewith usual test procedures, the statistical or theoretical valuesascribed for the upper and lower extremes of the safe torque range aresubject to empirical modification as more experience with the device isgained.

If it is desired to amplify the swing of scale 28 relative the free end36 of pointer 24, the pointer may be lengthened and anchored on arm 20at a desired point further out towards the free end of arm 20 so thatthe opposite deflections of arms 20 and 22 will deflect both pointer 24and scale 28.

The invention is not limited to the details illustrated and describedherein, but is intended to cover all substitutions, modifications andequivalents within the scope of the following claim.

I claim:

A device for measuring the .tenacity of self-releasing means which holdsa ski boot on a ski, comprising a dummy last consisting of asubstantially L-shape member having a foot portion and a stem portionintegrally connected to one another, the length of said foot portionbeing considerably longer than the width thereof, said foot portionbeing adapted to engage lengthwise within the foot of the boot, the freeend of the foot portion engaging in the toe portion of the boot on oneside of the boot, the juncture of the foot and stem portion engaging inthe heel portion of the boot on the opposite side of the boot, and thestern portion extending outwardly through the ankle of the boot, atorque bar non-rotatively affixed intermediate its ends to the top ofstem portion and providing two arms extending outwardly in oppositedirections from the stem portion, whereby to apply torque to the bootvia said L-shape member tending to cause said self-releasing means tofree .the boot from the ski, and means for measuring the deflection ofat least one arm relative to the stem portion upon application of saidtorque.

References Cited by the Examiner UNITED STATES PATENTS 2,698,757 1/55Berlenbach 28011.35

OTHER REFERENCES Torque Manual, 2nd edition, 1957, P. A. Sturtevant Co.,Addison, Ill., 27 pages. Pages 8, 10 and 13 relied on.

10 RICHARD C. QUEISSER, Primary Examiner.

ROBERT L. EVANS, Examiner.

